In the can handling art it is frequently necessary to remove individual cans one at a time from a conveyor delivering a row of like cans, and to place each can at a precise location in the periphery of a rotating turret. In known machines used to seam a can end to a can body, a long screw is used to receive each can in its screw thread, and by virtue of the screw thread profile to present each can to a recess in the periphery of a rotating star wheel. The star wheel is rotated so that each can in turn is presented to a work station at the rotating turret.
A geometrical limitation of such an arrangement arises from the necessity for the arc of rotation of the star wheel to coincide with the arc of rotation of the turret, so as to allow a can to be safely and stably deposited from the rotating star wheel on to the rotating turret. Such a coincidence is at best an instantaneous coincidence of two touching arcs, or at worst an overlapping mismatch of two intersecting arcs. Neither such an instantaneous coincidence, nor such a mismatching, of the two arcs permits the satisfactory insertion of a closely fitting mandrel into a can as it is delivered by the star wheel on to the turret as both continue their respective rotations.
The present invention seeks to provide a transfer arrangement for delivering cans from a rotating star wheel to a rotating turret in such a way that a closely fitting mandrel can be safely inserted, at least partly, into a can during its transfer from the rotating star wheel to the rotating turret.
U.S. Pat. No. 4,059,186 (Aschberger) has a similar objective, and provides in an infeed transfer apparatus for transferring articles to a rotating table for cooperation there with successive, circumferentially-spaced article treatment means carried on said table:
(a) a turret member mounted for rotation about a fixed axis parallel with an axis of rotation of the rotating table;
(b) a plurality of article holders extending radially from the turret member at positions spaced around the periphery thereof and arranged for movement toward and away from said fixed axis;
(c) holder operating means comprising (i) a stationary annular cam disposed concentrically about said fixed axis, and (ii) for each such holder, a cam follower coupled to the holder, and a spring biasing means adapted to bias the holder into contact with said cam; and
(d) an article guide rail extending around a part of said turret member and spaced radially therefrom, said guide rail having a first arcuate part which is concentric with the turret, and a second arcuate part which is continuous with said first part and which is concentric with said rotating table.